The present invention relates to an air dryer cartridge, in particular for a compressed air treatment system of commercial vehicles.
Air dryer cartridges of this type are used, for example, in commercial vehicles, such as trucks and tractors. These frequently have one or more compressed air consumers, such as, for example, brake systems or pneumatic suspension systems, which have to be supplied with compressed air. The compressed air is typically provided by a compressor, for example a reciprocating piston compressor driven by a drive engine of the vehicle. In order to ensure fault-free operation of the compressed air consumers, the compressed air provided by the compressor customarily has to be treated further. In the compressed air treatment systems provided for this purpose, the compressed air is cleaned of dirt particles which were already contained in the sucked-up air, and also of oil and soot particles which are admitted into the compressed air during the compression process by the compressor, and moisture present in the compressed air is separated off. For this purpose, the compressed air treatment systems of commercial vehicles generally have air dryer cartridges which can dehumidify the compressed air and can preferably also absorb oil and dirt particles.
Conventional air dryer cartridges have a cartridge housing with a closed housing cover, an inner housing arranged in the cartridge housing, a drying agent which is accommodated in an intermediate space between the cartridge housing and the inner housing, and a filter device, which is arranged within the cartridge housing, for cleaning the compressed air. During the normal operation of the air dryer cartridge, the compressed air first of all flows through the filter device before entering the drying agent. For the regeneration mode of the air dryer cartridge, in which the flow passes through the air dryer cartridge in the reverse direction, a bypass for bypassing the filter device is generally provided and a nonreturn valve is arranged in said bypass. Such an air dryer cartridge is disclosed, for example, in WO 2004/011125 A2. In said known air dryer cartridge, the nonreturn valve is fitted on a coalescence filter parallel thereto.
The invention is based on the object of providing an improved air dryer cartridge with a simple design.
This object is achieved by an air dryer cartridge in accordance with embodiments of the invention. Advantageous refinements of the invention are described and claimed herein.
The air dryer cartridge according to the invention has a cartridge housing with a closed housing cover; an inner housing arranged in the cartridge housing; a drying agent which is accommodated in an intermediate space between the cartridge housing and the inner housing; a filter device which is arranged within the cartridge housing and is positioned upstream of the drying agent in the compressed air flow, based on a normal operation of the air dryer cartridge; a bypass for bypassing the filter device; and a nonreturn valve which is arranged in the bypass, is formed integrally with the inner housing and blocks a compressed air flow in the direction of the drying agent and permits a compressed air flow in the direction from the drying agent.
According to the invention, it is proposed to form the nonreturn valve integrally with the inner housing. By means of this measure, the number of individual components can be reduced and the design and assembly of the air dryer cartridge can be simplified.
In an advantageous refinement of the invention, the inner housing and/or the nonreturn valve are/is manufactured from a plastics material. In this refinement, the nonreturn valve can preferably be injection molded onto the inner housing, or inner housing and nonreturn valve can be produced by a two-component injection molding process. The inner housing and the nonreturn valve can preferably be manufactured from the same plastics material or from different plastics materials. In this connection, the term plastics material is basically intended to include all types of plastics, in particular also elastomers with regard to the nonreturn valve. In addition, in this connection, the term plastics material is intended to include materials made from one material and also materials made from two or more different materials.
In an advantageous refinement of the invention, the nonreturn valve has a valve flap which is integrally formed on the inner housing. The valve function of the nonreturn valve can preferably be achieved by a shaping and/or choice of material of the valve flap and/or a shaping of the connection between valve flap and inner housing.
In an advantageous refinement of the invention, compressed air can flow through the nonreturn valve in a direction substantially parallel to a longitudinal axis of the air dryer cartridge, i.e. substantially axially.
In this refinement, the nonreturn valve can preferably have a valve flap with a free end which is supported on an inner circumferential surface of the cartridge housing, preferably on a portion of the inner circumferential surface of the cartridge housing, which portion runs substantially parallel to the longitudinal axis of the air dryer cartridge.
In another advantageous refinement of the invention, compressed air can flow through the nonreturn valve in a direction substantially transversely with respect to a longitudinal axis of the air dryer cartridge, i.e. substantially radially. In this refinement, the nonreturn valve can be positioned further inward in the cartridge housing and is thus, for example, better protected against external mechanical loads on the cartridge housing. In addition, in this refinement, a space region within the cartridge housing, which space region lies in the radial direction outside the nonreturn valve, can preferably be at least partially used for accommodating the drying agent.
In this refinement, the nonreturn valve can preferably have a valve flap with a free end which is supported on a flange inner surface of the fastening flange, said flange inner surface facing the inner housing.
In a further advantageous refinement of the invention, the filter device is arranged substantially coaxially with respect to the longitudinal axis of the air dryer cartridge. In this refinement, compressed air flows through the filter device preferably in the radial direction transversely with respect to the longitudinal axis of the air dryer cartridge. In addition, in this refinement, a space region within the cartridge housing, said space region lying in the radial direction outside the filter device, can preferably be at least partially used for accommodating the drying agent. In this case, the filter device is configured, for example, as a coalescence filter or oil filter.
In another advantageous refinement of the invention, the filter device is oriented substantially transversely with respect to the longitudinal axis of the air dryer cartridge. In this refinement, compressed air flows through the filter device preferably in the axial direction parallel to the longitudinal axis of the air dryer cartridge. The filter device in this case is configured, for example, as a coarse filter.
The inner housing preferably has a first inner housing part and a second inner housing part. The first inner housing part is preferably arranged radially outside the second inner housing part, and the second inner housing part is movable relative to the first inner housing part in the axial direction parallel to the longitudinal axis of the air dryer cartridge. In this refinement, a pretensioning element is preferably provided which presses the second inner housing part in the direction of the housing cover of the air dryer cartridge in order to compress the drying agent.
In yet another advantageous refinement of the invention, the air dryer cartridge has a fastening flange for closing an open end side of the cartridge housing, said end side facing away from the housing cover, and for fastening the air dryer cartridge to a compressed air treatment device. In this refinement, the inner housing is preferably sealed off from the fastening flange via a sealing lip. Said sealing lip is preferably manufactured from a plastics material. In this connection, the term plastics material is intended basically to include all types of plastics, in particular even elastomers. In addition, in this connection, the term plastics material is intended to include materials made from one material and also materials made from two or more different materials. The sealing lip can be manufactured from the same or from a different plastics material than the nonreturn valve.
The present invention is advantageously suitable in particular for use in compressed air treatment systems of a commercial vehicle.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.